1. Field of the Invention
The invention relates to an ignition device in a motor vehicle for triggering a restraining device, in particular, a seat belt tightening device or airbags, wherein the ignition device in the area of its forward end has an ignitor, such as an ignition cap or an ignition resistor arranged in a powder chamber filled with a powder, as well as electronic components which are arranged on a MID support.
2. Description of the Related Art
An ignition device which is installed in a drive device for a restraining device of a motor vehicle is known, for example, from AT 000 522 U1. For preventing ignition misfires, the ignition device has electronic components, in particular, inductive resistors, which are freely soldered to the supply wires of the ignition device for supplying the ignition energy and are embedded in plastic material by injection molding or by casting. The employed electronic components are relatively robust components such as inductive resistors.
From German patent DE 196 10 799 C1 an ignition device of the aforementioned kind is known in which semiconductor components in the form of integrated circuits are used also. The electronic components can be mounted on a MID support (MID=molded interconnects device). Such supports are, for example, produced in a two-step injection molding process wherein a base member of a first plastic material component is embedded in a second plastic material component by injection molding and one of the two plastic material components can be provided by an electrochemical electroplating process with a surface metallization while the other of the two plastic material components does not accept such a metallization by electroplating. The metallization by electroplating is provided for forming strip conductors which contact and connect the electronic components to be provided on the MID support.
Other methods for manufacturing MID supports are known: for example, so-called photo imaging technologies or film technologies. These technologies are, for example, described in the proceedings of the Third International Congress xe2x80x9cMolded Interconnect Devicesxe2x80x9d, Sep. 23-24, 1998, Erlangen, Germany (ISBN 3-87525-111-3). In each case, strip conductors are arranged on the injection-molded base body.
It is an object of the present invention to provide an improved ignition device of the aforementioned kind whose manufacture, in comparison to that of the ignition device known from German patent DE 196 10 799 C1, is simplified.
In accordance with the present invention, this is achieved in that the MID support has at least one connector pin which is formed as a unitary part of the MID support and which is provided with at least one metallized area for contacting the electronic components.
In the ignition device according to the invention the one or more connector pins for contacting the ignition device are thus embedded by injection molding during the manufacture of the MID support and are then provided with a corresponding metallization or metallized areas by electroplating which provide the contact surfaces.
In a preferred embodiment of the ignition device according to the invention at least a part of the wall of the powder chamber is also formed by injection molding during the manufacture of the MID support and is formed as a unitary part thereof.
For completing the ignition device, optionally after embedding the electronic components in a sealing component, a further plastic material component is advantageously connected by injection molding to the MID support. This further plastic material component can be a soft plastic material component which forms a sealing bead extending about the outer periphery of the ignition device.